Vena cava filter with filament

ABSTRACT

A vena cava filter is described, having one or more frame members or an elongated member arranged in helical fashion. A plurality of filaments connect frame members or portions of the elongated member. The filaments may be made of suture material. Hooks may be placed on a free end of the filaments, along the length thereof, or on one or more frame members to engage the blood vessel wall and anchor the filter. A retrieval member may be positioned on the filter to facilitate withdrawal of the filter from the blood vessel.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.12/093,814 filed Jun. 8, 2009, now U.S. Pat. No. 9,131,999, which is aU.S. national stage application under 35 USC § 371 of InternationalApplication No. PCT/US2006/044826, filed Nov. 17, 2006, which claims thebenefit of priority to U.S. Application No. 60/737,895, filed Nov. 18,2005, each of which is incorporated by reference in its entirety intothis application.

BACKGROUND

Inferior vena cava (IVC) filters are devices configured for insertioninto the inferior vena cava to capture particles that may be present inthe blood stream which, if transported to, for example, the lungs couldresult in serious complications and even death. Typically, IVC filtersare utilized in patients who have a contraindication to anticoagulationor in patients developing clinically apparent deep vein thrombosis (DVT)and/or pulmonary embolism (PE). Patients who have recently suffered fromtrauma, have experienced a heart attack (myocardial infarction), or whohave undergone major surgical procedure (e.g., surgical repair of afractured hip, etc.) may develop clinically apparent DVT. When athrombus clot loosens from the site of formation and travels to thelung, it may cause PE, a life-threatening condition. An IVC filter maybe placed in the circulatory system to intercept one or more clots andprevent them from entering the lungs. IVC filters are either permanentor retrievable.

There are many different configurations for IVC filters, including thosethat include a central hub from which extend a plurality of struts thatform filter baskets having a conical configuration, such as disclosed inU.S. Pat. No. 6,258,026, which is incorporated by reference in itsentirety into this application. Other IVC filter configurations utilizewires and/or frame members to form straining devices that permit flow ofblood while trapping larger particles. IVC filters are generallyconfigured for compression into a small size to facilitate delivery intothe inferior vena cava and subsequent expansion into contact with theinner wall thereof. The IVC filter may later be retrieved from thedeployed site by compressing the legs, frame members, etc., depending onthe filter configuration. Typically, an IVC filter will include hooks oranchoring members for anchoring the filter in position within theinferior vena cava. The hooks may be more elastic than the legs or framemembers to permit the hooks to straighten in response to withdrawalforces, which facilitate withdrawal from the endothelium layer of theblood vessel without risk of significant injury to the vessel wall.

Applicants have recognized that it would be desirable to provide an IVCfilter that incorporates one or more filaments, such that thefilament(s) provide a framing function and/or a filtering function, inorder to provide advantageous properties to the IVC filter. Embodimentsof such IVC filters are described herein.

BRIEF SUMMARY OF THE INVENTION

Accordingly, IVC filters with one or more filaments are describedherein. In one embodiment, a blood vessel filter includes two or moregenerally arcuate frame members spaced apart and arranged along alongitudinal axis that extends through the two or more frame members,and a plurality of filaments connecting the frame members. The framemembers may include a first section and a second section, the firstsection having a portion disposed inside the second section. In anotherembodiment, a blood vessel filter includes an elongated member arrangedin a helical radially expanding path about and along a longitudinalaxis, and a plurality of filaments connected to the member.

In yet another embodiment, an implantable medical device includes acontinuous generally circular member defining a frame having an openinterior portion, and a plurality of filaments attached to the frame,each filament having a first end connected to the frame at a first pointand a second opposite end connected to the frame at a second pointdifferent from the first point, the filaments together defining agenerally planar mesh-like surface spanning the interior portion of theframe. In another embodiment, an implantable medical device includes asupport structure having an open proximal end, and one or more filamentsattached to the frame to define a generally planar mesh-like surfacespanning the open proximal end.

These and other embodiments, features and advantages will become moreapparent to those skilled in the art when taken with reference to thefollowing more detailed description of the invention in conjunction withthe accompanying drawings that are first briefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of one embodiment of a filter withframe members.

FIG. 2A is a side perspective view of another embodiment of a filterwith frame members that are adjustable.

FIG. 2B is a cut-away view of one embodiment of a frame member of FIG.2A.

FIG. 2C is a cut-away view of another embodiment of a frame member ofFIG. 2A, shown in a collapsed configuration.

FIG. 2D is a cut-away view of the embodiment of a frame member of FIG.2C, shown in an expanded configuration.

FIG. 3 is a side perspective view of an embodiment of a filter with anelongated member.

FIG. 4 is a perspective view of another embodiment of a filter with aframe member having an open interior portion spanned by a generallyplanar mesh-like surface.

FIG. 5A is a perspective side view of another embodiment of a filterwith a support structure having an open proximal end spanned by agenerally planar mesh-like surface.

FIG. 5B is a top view of a variation of the embodiment of FIG. 5A.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description should be read with reference to thedrawings, in which like elements in different drawings are identicallynumbered. The drawings, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theinvention. The detailed description illustrates by way of example, notby way of limitation, the principles of the invention. This descriptionwill clearly enable one skilled in the art to make and use theinvention, and describes several embodiments, adaptations, variations,alternatives and uses of the invention, including what is presentlybelieved to be the best mode of carrying out the invention.

The filter embodiments discussed below may be used for insertion intothe inferior vena cava or other blood vessels or cavities in a mammalianbody. As used herein, the term “suture material” means a material thatis, or could be, used as a suture thread by a surgeon, including, forexample, synthetic polymers, polyglycolic acid (PGA), polydioxanone(PDS), polyglactin, nylon, polypropylene (prolene), silk, catgut,non-absorbable/non-biodegradable materials, and combinations thereof.Included in the term “suture material” are both monofilament andmultifilament arrangements. Also, as used herein, the term “hook” meansa member configured to engage a blood vessel wall which may include, forexample, the hooks shown and described in U.S. Pat. No. 6,258,026, whichis incorporated by reference in its entirety into this application.

Referring to FIG. 1, one embodiment of a filter is illustrated. Filter10 includes two or more generally arcuate frame members that are spacedapart and arranged along a longitudinal axis L that extends through twoor more frame members. In the embodiment shown, frame member 12 ispositioned at a proximal end of filter 10 and frame member 13 is spacedapart from frame member 12 along a longitudinal axis L of the filter.Spaced apart from frame member 13 along longitudinal axis L is framemember 14. The frame members 12, 13, 14 have a generally arcuate shape,which in some embodiments may be circular, elliptical, etc., and whichincrease in size in the distal direction such that the diameter D12 offrame member 12 is less than the diameter D13 of frame member 13, andthe diameter D13 of frame member 13 is less than the diameter D14 offrame member 14. In another embodiment, the diameters of all the framemembers are substantially equivalent, while in another embodiment onlysome of the frame members have diameters that are substantiallyequivalent. In one embodiment, the frame members decrease in diameterfrom a proximal end of the filter to a mid-region of the filter and thenincrease in diameter from the mid-region of the filter to a distal endof the filter. Other embodiments with respect to the shapes and sizes ofthe frame members in view of the examples provided are also possible andare within the scope of the invention, as one skilled in the art wouldappreciate. The frame members 12, 13, 14 of filter 10 are shown in anexpanded configuration, defining an expanded perimeter of the filter 10.For delivery of the filter 10 to a blood vessel, the frame members 12,13, 14 are compressed to a collapsed configuration. The frame members12, 13, 14 in the collapsed configuration define a collapsed perimeterof the filter 10 smaller than the expanded perimeter of the filter 10.

The frame members (or filaments) may be made of any material typicallyused for implantable medical devices as known to one skilled in the art,such as, for example, stainless steel, shape memory metals, shape memoryalloys, super elastic shape memory metal alloys, metal alloys, shapememory polymers, polymers, and combinations thereof. The frame membersmay also be made of a bio-resorbable material such as, for example, thematerials shown and described in U.S. Pat. No. 6,287,332; and U.S.Patent Application Publication No. 2002/0004060, which are incorporatedby reference in their entireties into this application.

The generally arcuate frame members 12, 13, 14 of filter 10 areconnected together via a plurality of filaments 16. In one embodiment,the filaments 16 include suture material, although in other embodiments,the filaments may include materials discussed above with respect to theframe members. The filaments 16 are attached to each frame member alongthe longitudinal axis L, as shown in filter 10. However, in otherembodiments, the filaments can be attached to every odd frame memberalong the longitudinal axis L (i.e., the most proximal frame member, thethird frame member counting from the proximal frame member, the fifthframe member, etc.), or every even frame member along the longitudinalaxis L, or every third frame member along the longitudinal axis L, etc.In other embodiments, one filament is attached to each frame member ofthe filter along the longitudinal axis L, while an adjacent filament isattached to every odd frame member, or every even frame member, or everythird frame member, etc. In still other embodiments, one or morefilaments could be attached to every odd frame member or every evenmember along the longitudinal axis L, while the remainder of thefilaments are attached to each frame member along the longitudinal axisL. Certainly other embodiments not specifically mentioned are alsowithin the scope of the invention with respect to attachment offilaments to frame members.

The filaments 16 are attached to the frame members 12, 13, 14 in filter10 by wrapping the filament one time around each frame member. However,other possibilities for attaching the filaments to the frame membersinclude wrapping the filament multiple times around the frame member,tying the filament to the frame member or members, heating the filamentadjacent to the frame member to create a bond therebetween, applying anadhesive to the filament and/or the frame member, applying a solvent tothe filament and/or frame member, etc. Of course, other possibilitiesfor attaching a filament to frame members known to one skilled in theart are also within the scope of this invention.

The filaments 16 of filter 10 extend beyond the most distal frame member14, having a free end attached to a hook 18. The hook 18 can have manydifferent configurations as known to one skilled in the art, such as,for example, the hooks disclosed in U.S. Pat. No. 6,258,026. While eachof the filaments 16 of filter 10 are shown with a hook attached to afree end, in other embodiments one or more filaments may terminate atthe most distal frame member without a free end, while other filamentsextend beyond the most distal frame member, having a free end with ahook attached. In other embodiments (see FIG. 2), none of the filamentsextend beyond the most distal frame member, in which case the hook 18may be attached to the frame member or to the filament at some pointalong its length. The hook 18 is configured for engaging the wall of theblood vessel into which the filter 10 is deployed and may be made of anymaterial discussed above with respect to the frame members. In oneembodiment, the hook contains a linear portion connected to an arcuateportion that terminates in a point, as shown and described in U.S. Pat.No. 6,258,026. In one embodiment, the arcuate member has across-sectional area smaller than the cross-sectional area of the linearportion, as shown and described in U.S. Pat. No. 6,258,026. In thepreferred embodiments, each of the hooks has a largest diameter on itsarcuate portion of less than about 0.013 inches, preferably about 0.0085inches and most preferably 0.0105 inches. Details of the hooks are shownand described in U.S. patent application Ser. No. 11/429,975, filed May9, 2006, which application is incorporated by reference in its entiretyinto this application. Alternatively, the hooks can be those shown anddescribed in U.S. Patent Application Publication Nos. 2005/0101982 and2005/0131451, which are incorporated by reference in their entiretiesinto this application.

FIG. 2A shows another embodiment of a filter 20. Filter 20 is similar tofilter 10 in that it contains three frame members 22 connected togetherby filaments 26, which in one embodiment are made of suture material,and in other embodiments are made of materials discussed above inconnection with possible materials for the frame members. The filaments26 of filter 20 do not have a free end extending beyond the most distalframe member. Thus, while in some embodiments, the filaments may includea free end with a hook as described above, in other embodiments, a hookor hooks may be attached along the circumference of one or more framemembers or may be attached to one or more filaments along their length.Other embodiments include hooks on both a free end of the filament(s)and the frame member and/or along the length of the filament(s). Theframe members 22 are shown in this embodiment in a configuration inwhich the size of the frame members 22 increase in diameter from aproximal end to a distal end along a longitudinal axis. The framemembers 22, however, in filter 20 are unique in that the frame member 22are adjustable.

Specifically, frame members 22 include a first section 23 and a secondsection 24, the first section 23 having a portion disposed inside andslidable within the second section 24. Thus, the size and shape of theframe members 22 may be adjusted by moving the first section 23 withrespect to the second section 24. A limit member to prevent separationmay be included on either or both the first section 23 and the secondsection 24. In one embodiment, shown in FIG. 2B, a limit member is inthe form of a ring 28 coupled, connected to or molded onto the firstsection 23 of the frame member 22 about the portions that are disposedwithin the second section 24. In this embodiment, the second section 24of the frame member 22 contains a shoulder 27 positioned in a passage 21of the second section 24 adjacent both openings 29 through whichportions of the first section 23 are positioned. The shoulders 27 areconfigured to prevent passage of the rings 28 out of the openings 29,thereby preventing separation of the first section 23 from the secondsection 24. The rings 28 may be positioned anywhere along the length ofthe first section 23 and may be sized to provide a friction fit with thepassage 21 of second section 24 in order to prevent the first section 23from movement with respect to second section in the absence of aclinically significant force. Also, the passage 21 could contain twoadditional shoulders within the passage 21 and on opposite sides of therings 28 to prevent movement within the passage 21, thereby providing apredetermined constraint on the size and shape of the frame member 22.Of course, there are numerous possibilities for the limit member asunderstood by one skilled in the art.

For insertion into a blood vessel, the frame members 22 are placed in acollapsed configuration by moving a portion of the first section 23 intothe second section 24. In the collapsed configuration, the frame members22 define a first outer perimeter. Once inserted and positioned withinthe blood vessel, the frame members 22 are placed in an expandedconfiguration by moving a portion of the first section 23 that waspreviously inside the second section 24 out of second section 24. Theframe members 22 in the expanded configuration define a second outerperimeter greater than the first outer perimeter. Movement of a portionof the first section 23 out of the second section 24 to place the framemembers 22 in an expanded configuration may be accomplished by methodsknown to one skilled in the art, such as, for example, applying pressureto an interior surface of the frame members using a balloon catheter.

Referring now to FIGS. 2C and 2D, another embodiment for the framemembers 22 is illustrated. In this embodiment, the first section 23 canbe locked with respect to second section 24 following delivery into ablood vessel. As with the embodiment of FIG. 2A, first section 23includes limit members 28 that are positioned within passage 21 ofsecond section 24. Second section 24 contains shoulders 27, as in FIG.2A, but also contains tab members 25 that impart a locking function tothe frame members 22. Specifically, FIG. 2C illustrates the frame member22 in a collapsed configuration for delivery into a blood vessel, suchas the inferior vena cava, with limit members 28 positioned withinpassage 21 distant from the openings 29. After the filter has beenpositioned in the blood vessel, the frame member 22 is placed in anexpanded configuration following deployment thereof as described above,which is shown in FIG. 2D.

As the frame member 22 is expanded, the first section 23 has portionswithin the second section 24 that are moved out of the second section24. As these portions of first section 23 are moved with respect tosecond section 24, the limit members 28 are moved in a direction towardthe openings 29. Tab members 25 are flexible such that as limit members28 contact the tab members 25, the tab members 25 flex in a directiontoward the openings 29, permitting the limit members 28 to move towardthe openings. After the limit members 28 move past the tab members 25such that they are no longer in contact therewith, the tab members 25resiliently move back into their un-flexed position, thereby preventingmovement of the limit members 28 away from the openings 29, as shown inFIG. 2D. Due to the presence of the shoulders 27 on the second section24, the limit members 28 are also prevented from movement out of theopenings. Thus, the first section 23 is locked into position withrespect to the second section 24. The tab members 25 may be configuredto permit one-way movement (such that the first section 23 ispermanently locked with respect to the second section 24) or two-waymovement (such that the frame member 22 is collapsible to permit removalfrom the blood vessel), depending on whether the filter is intended tobe permanent or temporary. The frame member 23 can be made of a suitablematerial such as, for example, shape memory alloy, shape memory polymer,super elastic shape memory metal alloy, linear elastic shape memorymetal alloy. Alternatively, a biasing element can be provided in theinternal space 21 to bias the section 23 towards a deployedconfiguration. Preferably, at least the frame member 23 is made ofNitinol so that the frame member 23 self-expand into a largerconfiguration when placed in a suitably warm environment.

FIG. 3 illustrates another embodiment of a filter 30. Filter 30 includesan elongated member 32 arranged in a helical radially expanding pathabout and along a longitudinal axis L from a proximal end 34 to a distalend 38, the elongated member 32 having a free end at both the proximalend 34 and distal end 38. The elongated member 32 may be made of anymaterial discussed above with respect to the frame members of FIG. 1. Asshown, each of the filaments 36 are attached to the elongated member 32at points along each turn or successive winding of the helical path,although, as discussed above in reference to FIG. 1, numerouspossibilities exist for the attachment points of the filaments. Forexample, select filaments could be attached to every odd turn along thehelical path (i.e., counting the first turn as 1 and proceedingtherealong), or every even turn along the helical path, etc. Asdiscussed above, the method of attachment of the filaments 36 to theelongated member 32 can include use of adhesives, solvents, wrapping ofthe filament around the elongated member, tying the filament to theelongated member, etc.

Also, it should be appreciated for all embodiments described herein thatfilaments could be attached only to adjacent frame members or helicalturns, rather than extending down the length of the filter. Thus, forexample, referring to FIG. 3, a first set of filaments 36 could beattached only to the first helical turn and second helical turn, while asecond set of filaments 36 could be attached only to the second helicalturn and the third helical turn. Alternatively, select filaments couldextend down the length of the filter 30, attached to each helical turn,while other filaments are attached only to consecutive turns, or everyodd turn, or every even turn, etc. As with the filters 10 and 20, thefilaments 36 of filter 30 may extend beyond the distal end 38 having afree end to which a hook is attached. Alternatively, or in addition tothe preceding, hooks may be attached to the elongated member 32 alongits length and/or to the filaments along their length as would beappreciated by one skilled in the art. As with all embodiments describedherein (and those within the scope of the invention not specificallydescribed), the filaments may include a suture material or any of thosematerials discussed as possibilities for the frame members of FIG. 1.

Referring now to FIG. 4, another embodiment of a filter 40 isillustrated. Filter 40 includes a frame member 42 that is shown ascontinuous and generally circular, having an interior portion that isopen. The frame member 42 can be made of any material discussed abovewith respect to the frame members of FIG. 1. Attached to the framemember 42 are filaments 46 that span the open interior portion such thata first end of each filament is attached to the frame at a first pointand a second end of each filament is attached to a second pointdifferent from the first point, creating a generally planar mesh-likesurface 46 as shown in FIG. 4. In one embodiment the attachment pointsfor each filament 46 are spaced approximately equidistant to provide auniform mesh-like surface 46. The filaments 46 may include a suturematerial or any of those materials discussed as possibilities for theframe members of FIG. 1. Attached to a surface of the frame member 42are hooks 48, which can be configured as discussed above and made ofmaterials such as those discussed as possibilities for the frame membersof FIG. 1. The mesh-like surface can be provided with a suitable openarea ratio such that blood cells can pass through the mesh-like surfaceand the pressure drop across the mesh-like surface is generallyinsignificant. In the preferred embodiments, the open area ratio is atleast 10:1 and the pressure drop is less than 0.2 inch of Hg (assimulated in a 28 mm internal pipe diameter with fluid that simulatesblood flow).

The filter 40 can be configured in a first configuration smaller thanthe configuration shown in FIG. 4. For example, the filter 40 can betwisted into a figure-8 and bent at the mid-point of the figure-8 into asmaller generally circular configuration and loaded into a suitabledelivery catheter. Preferably, the filter 40 is sized and loaded into a?French internal diameter delivery catheter. Applicant has recognizedthat this embodiment provides for an advantage not heretofore availablein that the filter 40 can be delivered either from the jugular vessel orfemoral vessel without regard to the orientation of the filter 40.

Referring to FIG. 5A, another embodiment of a filter 50 is illustrated.Filter 50 includes a support structure 52, which in a preferredembodiment is a stent. In one embodiment, the support structure 52 is aring stent with anchors as described in U.S. Patent ApplicationPublication No. 2003/0158595, which is incorporated by reference in itsentirety into this application. In one embodiment, the support structure52 includes a cylindrical shape with a generally uniform distribution ofstruts 54. The struts 54 together form repeating diamond shapes aroundthe circumference of the structure 52 with a proximal end 56 and adistal end 58. The support structure may include hooks, which can beconfigured as discussed above and made of materials such as thosediscussed as possibilities for the frame members of FIG. 1, on theproximal end 56 and/or distal end 58. In addition, markers 55 mayoptionally be included on one or both of the proximal and distal ends56, 58, such as the marker elements described in U.S. Patent ApplicationPublication No. 2004/0015228, which is incorporated by reference in itsentirety into this application. The markers 55 preferably include aradiopaque material, such as, for example, tantalum, platinum, gold,iridium or a combination thereof. The markers 55 can be attached to thesupport structure using methods known to one skilled in the art (e.g.,laser welding) and can be arranged in a uniform pattern (e.g., everyother strut end, every third strut end, etc.) or a non-uniform pattern.In one embodiment, only a single marker 55 is attached to the proximalend 56 of the support structure 52.

In one embodiment, the filter 50 includes a covering material 60, suchas a graft member, positioned on an inner surface of the supportstructure 52, an outer surface of the support structure 52, or both. Thecovering material 60 may include a biocompatible material, such as, forexample, expanded polytetrafluoroethylene (ePTFE), polyester,polyurethane, fluoropolymers, such as perfouorelastomers and the like,polytetrafluoroethylene, silicones, urethanes, and combinations thereof,but in a preferred embodiment the covering material 60 includes ePTFE.In one embodiment, the covering material 60 includes an inner ePTFEgraft 62 and an outer ePTFE graft 64 that are fused together throughopenings between struts 54 to at least partially encapsulate the supportstructure 52. In the embodiment shown in FIG. 5A, the proximal endsurfaces of the support structure 52 are left uncovered by the coveringmaterial 60, in order, for example, to provide a platform for markers,hooks or both, and/or to provide an attachment point for one or morefilaments 62.

The filament or filaments 62 are attached to the support structure 52,spanning an open region at the proximal end 56 of the support structure52, to provide a mesh-like surface 64 configured to prevent the passageof blood clots or other debris entering through the open distal end 58of the support structure 52. In one embodiment, windings of a singlefilament or filaments 62 are positioned such that a first end of eachwinding or filament 62 is attached to the support structure 52 at afirst point and a second end of each winding or filament 62 is attachedto a second point different from the first point, creating a generallyplanar mesh-like surface 64. In one embodiment, the attachment pointsfor each winding or filament 62 are spaced approximately equidistant toprovide a uniform mesh-like surface 64. In another embodiment, thefilament or filaments 62 are twisted together, wrapped around adjacentstruts on the support structure, or are otherwise arranged in anon-uniform manner to provide a non-uniform mesh-like surface 64. Thefilament or filaments 62 may be attached to the support structure priorto or following the disposition of the covering material 60 inembodiments including a covering material 60. In addition to spanningthe open proximal end 56, the filament or filaments 62 may be disposedtransverse to the mesh-like surface 64, extending between the proximalend 56 and the distal end 58. Alternatively, the filament or filaments62 may be attached only to the proximal end 56 of the support structure52 (e.g., portions extending proximal of the covering material 60).

FIG. 5B is a top perspective view of alternate embodiment of the filter50 that includes a ring 66 to which the filament or filaments 62 areattached (e.g., by winding around, etc.) or that is created through theweaving of one or more filaments 62. The ring 66 facilitates passage ofa guidewire and can be utilized as a platform for attaching a retrievalmember. In embodiments including a ring 66 made of a metal or polymermaterial, for example, a retrieval member could be configured fortemporary attachment to the ring 66. The filter 50 is generallycollapsible from an expanded configuration with an expanded perimeter asshown in FIGS. 5A and 5B to a collapsed configuration with a collapsedperimeter smaller than the expanded perimeter (not shown). In oneembodiment, the filter 50 is collapsed to the collapsed configuration byapplying a force to the mesh-like surface 64 in a direction away fromthe filter 50. In one embodiment, a retrieval member is attached to themesh-like surface 64 and pulled so that the force applied to the surface64 is generally uniformly distributed. The retrieval member may bepermanently attached to the filament or filaments 62 forming themesh-like surface 64 or may be temporarily attached thereto forretrieval of the filter 50 from a deployed position in a blood vessel.In one embodiment, the retrieval member is attached (permanently ortemporarily) to the support structure 52.

As with the embodiment described above in connection with FIG. 4, themesh-like surface 64 can be provided with a suitable open area ratiosuch that blood cells can pass through the mesh-like surface 64 and thepressure drop across the mesh-like surface 64 is generallyinsignificant. In the preferred embodiments, the open area ratio is atleast 10:1 and the pressure drop is less than 0.2 inch of Hg (assimulated in a 28 mm internal pipe diameter with fluid that simulatesblood flow).

Delivery of various embodiments of the filter described herein can be byany suitable techniques. For example, the filter can be activelydelivered via a spring force provided in a delivery catheter. A coilspring can be coupled to a pusher member disposed in the lumen of thedelivery catheter. The coil spring is compressed prior to delivery. Onceactuated, the spring provides an abrupt kinetic force to the filter toeject the filter out of the delivery catheter. Alternatively, othermotive force such as a pressurized liquid can be used to eject (via anintermediate member such as a pusher in the lumen of the deliverycatheter) the filter out of the delivery catheter. Additionally, aballoon can also be used to ensure full radial expansion of each filter.

Each of the embodiments described herein may also include a retrievalmember to facilitate retrieval of the filter from the blood vessel inwhich it is placed. The retrieval member may be configured as a hook,loop, rod, shaft, etc., which cooperates with a removal device to permitremoval of the filter from the blood vessel. One example of a retrievalmember is disclosed in U.S. Pat. No. 6,156,055, which is incorporated byreference in its entirety into this application. The retrieval membermay be placed on the most proximal frame members (FIGS. 1-2), at theproximal end 34 of the elongated member 32 (FIG. 3), or along a surfaceof the frame member 42 (FIG. 4). Alternatively, the retrieval member maybe positioned along the length of a filament in any of the embodimentsdescribed herein, or on a more distal section of the filter (e.g., framemember 13 of FIG. 1, along the length of the elongated member 32 of FIG.3, etc.).

Each of the embodiments described herein can be utilized for a bloodvessel of at least 28 millimeters. Moreover, each of the embodimentsdescribed herein can be loaded into a delivery catheter having an insidediameter of less than about 10 French. The length of each embodiment,when deployed, can be about 50 millimeters or less.

Where the filter is to be utilized with bio-active agents to control theformation of emboli, bio-active agents can be coated to a portion or theentirety of the filter for controlled release of the agents once thefilter is implanted. The bio-active agents can include, but are notlimited to, vasodilator, anti-coagulants, such as, for example, warfarinand heparin. Other bio-active agents can also include, but are notlimited to agents such as, for example, anti-proliferative/antimitoticagents including natural products such as vinca alkaloids (i.e.vinblastine, vincristine, and vinorelbine), paclitaxel,epidipodophyllotoxins (i.e. etoposide, teniposide), antibiotics(dactinomycin (actinomycin D) daunorubicin, doxorubicin and idarubicin),anthracyclines, mitoxantrone, bleomycins, plicamycin (mithramycin) andmitomycin, enzymes (L-asparaginase which systemically metabolizesL-asparagine and deprives cells which do not have the capacity tosynthesize their own asparagine); antiplatelet agents such as G(GP)Ifb/IIIa2 inhibitors and vitronectin receptor antagonists;anti-proliferative/antimitotic alkylating agents such as nitrogenmustards (mechlorethamine, cyclophosphamide and analogs, melphalan,chlorambucil), ethylenimines and methylmelamines (hexamethylmelamine andthiotepa), alkyl sulfonates-busulfan, nirtosoureas (carmustine (BCNU)and analogs, streptozocin), trazenes-dacarbazinine (DTIC);anti-proliferative/antimitotic antimetabolites such as folic acidanalogs (methotrexate), pyrimidine analogs (fluorouracil, floxuridine,and cytarabine), purine analogs and related inhibitors (mercaptopurine,thioguanine, pentostatin and 2-chlorodeoxyadenosine {cladribine});platinum coordination complexes (cisplatin, carboplatin), procarbazine,hydroxyurea, mitotane, aminoglutethimide; hormones (i.e. estrogen);anti-coagulants (heparin, synthetic heparin salts and other inhibitorsof thrombin); fibrinolytic agents (such as tissue plasminogen activator,streptokinase and urokinase), aspirin, dipyridamole, ticlopidine,clopidogrel, abciximab; antimigratory; antisecretory (breveldin);anti-inflammatory: such as adrenocortical steroids (cortisol, cortisone,fludrocortisone, prednisone, prednisolone, 6a-methylprednisolone,triamcinolone, betamethasone, and dexamethasone), non-steroidal agents(salicylic acid derivatives i.e. aspirin; para-aminophenol derivativesi.e. acetominophen; indole and indene acetic acids (indomethacin,sulindac, and etodalac), heteroaryl acetic acids (tolmetin, diclofenac,and ketorolac), arylpropionic acids (ibuprofen and derivatives),anthranilic acids (mefenamic acid, and meclofenamic acid), enolic acids(piroxicam, tenoxicam, phenylbutazone, and oxyphenthatrazone),nabumetone, gold compounds (auranofin, aurothio glucose, gold sodiumthiomalate); immunosuppressives: (cyclosporine, tacrolimus (FK-506),sirolimus (rapamycin), azathioprine, mycophenolate mofetil); angiogenicagents: vascular endothelial growth factor (VEGF), fibroblast growthfactor (FGF); angiotensin receptor blockers; nitric oxide donors;anti-sense oligionucleotides and combinations thereof; cell cycleinhibitors, mTOR inhibitors, and growth factor receptor signaltransduction kinase inhibitors; retenoids; cyclin/CDK inhibitors; HMGco-enzyme reductase inhibitors (statins); and protease inhibitors.

This invention has been described and specific examples of the inventionhave been portrayed. While the invention has been described in terms ofparticular variations and illustrative figures, those of ordinary skillin the art will recognize that the invention is not limited to thevariations or figures described. In addition, where methods and stepsdescribed above indicate certain events occurring in certain order,those of ordinary skill in the art will recognize that the ordering ofcertain steps may be modified and that such modifications are inaccordance with the variations of the invention. Additionally, certainof the steps may be performed concurrently in a parallel process whenpossible, as well as performed sequentially as described above.Therefore, to the extent there are variations of the invention, whichare within the spirit of the disclosure or equivalent to the inventionsfound in the claims, it is the intent that this patent will cover thosevariations as well. Finally, all publications and patent applicationscited in this specification are herein incorporated by reference intheir entirety as if each individual publication or patent applicationwere specifically and individually put forth herein.

1-20. (canceled)
 21. A blood vessel filter for deployment in a bloodvessel having a blood vessel wall, comprising: a) a circumferentiallyextending rounded filter frame having an open interior portion and afirst diameter; b) multiple transverse filaments that extend from oneportion of said frame to another portion of said frame; c) wherein saidfilaments are circumferentially spaced around said frame and each ofsaid filaments spans the open interior portion; d) wherein saidfilaments form a mesh like surface that allows fluid and blood cells topass through but that captures blood clots; e) a catheter having a lumenwith a lumen diameter that is smaller than said first diameter; f) saidfilter frame having a deployed configuration wherein said frame isexpanded and having the first diameter and a storage configurationwherein said filter frame is formed into a smaller configuration havinga second diameter that is smaller than said first diameter; wherein saidfilter frame is twisted into a configuration defined by multiple loopsand bent to obtain the storage configuration; g) wherein the storageconfiguration enables the filter frame to occupy said catheter lumen;and h) one or more anchors on said frame that are positioned to anchorsaid frame to a blood vessel wall.
 22. The filter of claim 21 whereinthe frame is generally circular.
 23. The filter of claim 21 wherein atleast one said anchor is a hook.
 24. The filter of claim 21 wherein themesh like surface has an open area ratio of at least 10:1.
 25. Thefilter of claim 21 wherein there is a pressure drop across the filament,and the pressure drop across the filament is less than 0.2 inches Hg.26. The filter of claim 21 wherein the catheter is sized and shaped todeliver the filter either from a jugular vessel or a femoral vessel. 27.The filter of claim 21 wherein the filaments are of a suture material.28. The filter of claim 21 wherein there are multiple, circumferentiallyspaced apart anchors.
 29. The filter of claim 21 wherein at least someof the filaments are radially extending.
 30. The filter of claim 21wherein at least some of the filaments are generally parallel.
 31. Ablood vessel filter for deployment in a blood vessel having a bloodvessel wall, comprising: a) a circumferentially extending rounded filterframe having an open interior portion; b) multiple filaments that extendfrom said frame and into said interior portion; c) wherein saidfilaments form a mesh structure in said open interior portion thatallows fluid and blood cells to pass through but that captures bloodclots; d) a catheter having a catheter lumen having a catheter lumendiameter; e) said filter frame having a first deployed configurationwherein said frame is expanded to a first larger diameter and will notfit in said catheter lumen, and a second storage configuration that hasa second smaller diameter that is smaller than said first largerdiameter; and f) wherein in said storage configuration said filter hasbeen twisted into multiple rounded subsections, each rounded subsectionhaving a second smaller filter diameter that is about the same diameteras said catheter lumen diameter, enabling the filter frame to occupysaid catheter lumen.
 32. The filter of claim 31 wherein the frame is anendless loop.
 33. The filter of claim 31 wherein at least one anchor ismounted on said frame.
 34. The filter of claim 31 wherein the meshstructure has an open area ratio of at least 10:1.
 35. The filter ofclaim 31 wherein there is a pressure drop across the filaments, and thepressure drop across the filaments is less than 0.2 inches Hg.
 36. Thefilter of claim 31 wherein the catheter is sized and shaped to deliverthe filter either from a jugular vessel or a femoral vessel.
 37. Thefilter of claim 31 wherein the filaments are of a suture material. 38.The filter of claim 31 wherein there are multiple, circumferentiallyspaced apart anchors.
 39. A method of deploying a blood vessel filter ina blood vessel having a blood vessel wall, the filter comprising: a) acircumferentially extending rounded filter frame having an open interiorportion and a first maximum width; b) multiple transverse filaments thatare spaced circumferentially around said frame, said filaments spanningacross the open interior portion; c) wherein said filaments form a meshlike surface that allows fluid and blood cells to pass through but thatcaptures blood clots; d) a catheter having a lumen with a lumen diameterthat is smaller than said first maximum width; e) said filter framehaving a deployed configuration wherein said frame is expanded into thefirst maximum width and a storage configuration having a storage widththat is smaller than said first maximum width of said deployedconfiguration; and f) one or more anchors on said frame that arepositioned to anchor said frame to a blood vessel wall; and wherein themethod comprises the steps of: moving said filter frame from saiddeployed configuration to said storage configuration by twisting saidframe into a configuration that includes multiple rounded subsections,each said subsection having a width that is smaller than said firstmaximum width; and bending the frame of the smaller subsections into agenerally circular configuration that enables the filter frame to occupysaid catheter lumen, loading the filter into said catheter for deliveryto the blood vessel.
 40. The method of claim 39 wherein the roundedfilter frame is generally circular.